1. Field of the Invention
The present invention relates to an ultrasonic observing apparatus, a control method for the ultrasonic observing apparatus, an ultrasonic observing system and an ultrasonic diagnostic apparatus for performing signal processing on an echo signal obtained by transmitting ultrasonic pulses from an ultrasonic transducer to living body tissue and receiving ultrasonic pulses reflected from the living body tissue to create an ultrasonic tomographic image.
2. Description of the Related Art
An ultrasonic diagnostic apparatus, conventionally, repetitively transmits ultrasonic pulses to living body tissue from an ultrasonic transducer and receives an ultrasonic pulse echo signal reflected from the living body tissue to display information in the living body as an ultrasonic tomographic image being a visible image.
There are two types of ultrasonic diagnostic apparatuses depending on the scanning system: electronic scanning to scan a body cavity by electronically driving an ultrasonic transducer built in an ultrasonic endoscope or an ultrasonic probe used by being inserted into a channel for insertion of a treatment instrument of the endoscope, and mechanical scanning to scan the body cavity by mechanically rotating the transducer.
For example, an electronic scanning ultrasonic diagnostic apparatus described in Japanese Patent Laid-Open No. 6-47043 includes an ultrasonic transducer having a plurality of transducer elements. The apparatus drives the transducer elements of the ultrasonic transducer by electronically switching among the devices so that the apparatus can scan a body cavity to obtain an ultrasonic tomographic image.
On the other hand, a mechanical scanning ultrasonic diagnostic apparatus described in Japanese Patent Laid-Open No. 2001-333906 mechanically rotates an ultrasonic transducer so that the apparatus can scan a body cavity to obtain an ultrasonic tomographic image.
The ultrasonic observing apparatus used in the electronic scanning ultrasonic diagnostic apparatus connects to the electronic scanning ultrasonic endoscope or the electronic scanning ultrasonic probe to electronically drive the connected ultrasonic endoscope or ultrasonic probe. Meanwhile, the ultrasonic observing apparatus used in the mechanical scanning ultrasonic diagnostic apparatus connects to the mechanical scanning ultrasonic endoscope or mechanical scanning ultrasonic probe to mechanically drive the connected ultrasonic endoscope or ultrasonic probe.
The mechanical scanning ultrasonic endoscope or mechanical scanning ultrasonic probe mechanically rotates an ultrasonic transducer by 360 degrees to scan a body cavity, so that the scanning range cannot be changed, a frame rate being fixed and a scanning speed being slow. In addition, since the mechanical scanning ultrasonic endoscope or mechanical scanning ultrasonic probe cannot perform transmission for a plurality of times with an ultrasonic transducer being fixed at the same position, a scan is possible only in a B mode but not in a color flow mode.
Consequently, if a conventional mechanical ultrasonic observing apparatus does not need a scan in a color flow mode, arithmetic amount in the ultrasonic observing apparatus is comparatively small and a frame rate does not decrease by arithmetic time.
On the other hand, the electronic scanning ultrasonic endoscope or electronic scanning ultrasonic probe scans a body cavity by electronically driving a plurality of transducer elements composing the ultrasonic transducer, so that a scanning range can be changed to improve a frame rate compared to the mechanical scanning. In addition, the electronic scanning ultrasonic endoscope or electronic scanning ultrasonic probe can change a scanning method, making a scan possible in various modes such as a color flow mode and a power flow mode in addition to a B mode.